It is well known in technique to have to carry out, in a very large number of mechanical applications, the centering of endless belts moving on rollers. Said centering is required to correct the misplacements of the belts, as they move on the rollers supporting them and causing their motion and tensioning, which misplacements may be determined by external stresses, by inner strains and/or by the imperfectly cylindrical configuration of the belts and of the rollers.
The problem arises, for example, in belt conveyors, in belt presses and in belt-sanding machines. It is particularly felt in belt sanders for wooden floors (especially wood-block flooring), wherein an endless abrasive belt is rotated on two rollers--a driving roller and a tension roller--which are often cantilevered.
According to known technique, either fixed or self-centering arrangements are adopted. In the first case, it is not possible to self-center the belt, the misplacements of which must therefore be tolerated, or corrected by hand if they become intolerable. In the second case, self-centering is guaranteed, but--in the constructions realized up-to-date--the centering device usually takes up a lot of space on both sides (which is particularly prejudicial in belt sanders for wooden floors) and, furthermore, it provides for the use of position sensors and actuators, which makes it very complicated and costly.
The object of the present invention is to eliminate the drawbacks of known technique by supplying an automatic mechanical belt centering device, of efficient working and simple construction, which can thus be used in all those cases requiring a practical--but not too costly and complicated--solution of the problem.